So is even doing any challenging content, using minimum ilvl when doing synced runs, etc., etc. Or, in less loaded a term, optional challenge.
It is an option to put in more effort so you're not so damn bored. Since anyone likely to use said option would tend to make full use of the full kits they're nerfing their individual skill/AA potencies to be able to use, the result is the same, so you could still do that in matchmaking without it negatively affecting an average run (as if that weren't already subject to the first ego-tripping tank, princess healer, or no-AoEs/CDs DPS one comes across).
Scaling up, as done in the examples mentioned earlier, has no impact on power creep nor gear progression. Low-level players do not find their power varying based on their party. They simply find their party members' power levels all looking the same as theirs regardless of those members' actual levels relative to their own.And it's not as simple as you think, scale up has its own set of the problem. Power creep and trivialize gear progression are the two of many, and a low level player will suddenly find themself become significant more powerful when pair up with a high level player, and that's not necessary a good thing. Forgot the names but there have been a few games that use dynamic scaling and most players hate it, 'cause it eliminate the sense of actual progression.
The reason a high level player think that kind of system is "fine" because it benefit them, but that benefit come as detriment to people who new to the games. Between some "minor" inconvenience to the max player (and face it, most even don't run into that often) or destroying the lvling process of new players, it's very clear what should take a much higher priority to preserve.
There has also been no impact from level scaling systems on the leveling process of new players except in that their queue times get greatly reduced for/in leveling dungeons.
Better netcode? More player-friendly glamour systems? Account-wide store purchases? Avoid at all costs; another MMO might already have those elements of polish/convenience, and we wouldn't want XIV to be any less unique in not having them.